1. Field of the Invention
The present invention relates to telecommunications and, more particularly, to methods and systems for analyzing the accuracy of a wireless location technology used in a wireless telecommunications network.
2. Description of Related Art
The Federal Communications Commission (FCC) has adopted rules to implement enhanced 911 (E911) services for wireless calls. In Phase I of the E911 requirements, wireless carriers are required to provide the Public Safety Answering Point (PSAP) with the telephone number of the originator of a 911 wireless call and the cell site or base station serving the call originator. In Phase II of the E911 requirements, wireless carriers are also required to provide the PSAP with an Automatic Location Identification (ALI) of the 911 wireless call originator. For handset-based wireless location technologies, the FCC standards require the ALI to have a location accuracy of 50 meters for 67 percent of the calls and 150 meters for 95 percent of the calls.
The FCC has provided non-mandatory guidelines and suggestions for determining whether wireless location systems comply with the FCC's accuracy standards in its “Guidelines for Testing and Verifying the Accuracy of Wireless E911 Locations Systems,” OET Bulletin No. 71 (Apr. 12, 2000). The FCC's Guidelines suggest an empirical approach for verifying compliance with its accuracy standards. Specifically, the FCC's Guidelines suggest performing tests at various sample locations to determine the distance between the actual location and the location reported by the ALI system. The FCC's Guidelines also provide a table indicating, for various sample sizes, how many location measurements need to have location errors less than 50 meters and how many need to have location errors less than 150 meters in order to demonstrate compliance at the 90% confidence level.
The statistical approach given in the FCC's Guidelines has several drawbacks. First, it is rather cumbersome. Second, the approach does not provide a measure of how accurate the wireless location system is. The latter point is significant in that wireless location services are of interest not only because of the FCC's mandates but also because other entities may be interested in obtaining location information, e.g., to provide location-based services to wireless customers. Thus, there is a need to efficiently analyze the accuracy of wireless location technologies with regard to the requirements of potential consumers of location information, as well as for compliance with FCC's E911 requirements.